Electrically powered devices and equipment require that electricity flow the instant the equipment's switch is turned on. Electrical consumers assume that the power system has the generating capacity, or sources, in sufficient amount to provide all electrical loads with the power needed to turn on and keep those loads operating as long as needed. However, as electrical energy demand continues to dramatically increasing worldwide, as new types of electrical loads are continuously being connected, and as traditional fossil fuels are being replaced by renewable sources, a clear and urgent need for massive energy storage has become vital. Without bulk energy storage, the probability that electrical equipment might not turn on when the switch is turned on and then stays on is increasing exponentially as time passes.
In order to provide consumers with electricity when it is needed, high density energy storage systems that are connected to the power system at all times are used. The principle is to store excess energy produced from renewable sources during periods of low demand in order to supplement the erratic, non-dispatchable, and more costly renewable sources during the hours of high demand.
Due to space, economic, and mobility constraints, the energy density in these storage systems must be maximized. The most prevalent High Density Energy Storage Systems (HDESS) today consist of interconnected lithium ion cells. The number of cells can vary from one cell as used in small instruments, to a few cells as in smartphones, to hundreds of thousands of cells as used in battery banks in electrical utility substations.
Compaction of battery banks has been the predominant design option in order to increase energy density. Reduced battery pack sizes have been achieved by reducing the spacing between the cell electrodes and reducing the thickness of electrical and thermal insulation. However, by reducing cell and battery pack dimensions, there is an increased propensity for lithium ion powered devices and battery banks to ignite and/or explode violently. The close proximity of heat generating components with reduced heat dissipation can create thermal runaway effects, which have been documented in the technical literature and the media to lead to serious fires and explosions. This type of runaway phenomenon also applies to other battery types and other high energy density technologies.
Also contributing to the severity of lithium ion battery fire is the extremely high rate of energy release once the cells have been compromised. For comparison, the energy release rates of lithium ion cells is higher than that of liquid fuels such as gasoline and mineral oil. The heat flux driven by the elevated energy release rates is what can ignite neighboring equipment and cause collateral damage as these fires spread at very high speeds away from their source of origin.
Compounding the problem are two clear trends: 1) A further increase in energy densities by improving cell chemistry and by more miniaturization of the storage banks; and 2) A continued increase in the ratings of the battery banks. For utility power system applications the required battery banks will range from a few megawatts to several gigawatts in power ratings, and corresponding increased energy ratings depending on the applications. For example, at the power distribution level, batteries rated 10 MW at 40 MWh have already been installed. For transmission applications typical ratings could be about 1.6 GW at 35 GWh.
Such enormous amounts of energy concentrated in relatively compact installations must be confined in the event the energy is suddenly released due to a malfunction, accident, or thermal or electrical insulation breakdown. Currently, utility and industrial-size battery banks are packaged in metal enclosures, which resemble modified shipping containers. However, under the intense and long duration fire of a HDESS, such as lithium ion battery banks, these enclosures could explode or rupture and the fire could extend to other parts of the facility, putting equipment, personnel and the public at risk.
The present invention relates to enclosures made out of refractory material to effectively contain the extreme thermal hazards of fires and explosions caused by refineries, large energy-storage battery banks, electrical transformers, and oil-filled transformers in power substations, as well as extreme fires and explosions created by HDESS such as: utility scale lithium ion battery banks; zinc, lead and other metal battery banks; hydrogen fueled arrays; supercapacitor sets; charging stations; and liquefied natural gas tanks.